A) Field of the Invention
The present invention relates to a semiconductor device and its manufacture method, and more particularly to a semiconductor device having a film for applying strain to a channel of a MIS transistor formed on the surface of a semiconductor substrate, and its manufacture method.
B) Description of the Related Art
Limitations are becoming imposed on miniaturization of a MIS transistor in conformity with scaling rules. Attention has been paid to techniques for raising a carrier mobility by introducing strain in a channel and changing the physical property of channel material. In a semiconductor device disclosed in JP-A-2003-273240, an NMOS transistor is covered with an insulating film accumulating tensile stress therein to induce tensile stress to the channel region, and a PMOS transistor is covered with an insulating film accumulating compressive stress therein to induce compressive stress to the channel region.
By applying the stress to the channel region, a mobility of carriers moving in the channel can be raised.
JP-A-2005-353675 discloses techniques of forming recesses in source and drain regions, burying a silicon nitride film accumulating stress therein in the recesses to thereby increase strain in the channel region. By increasing strain in the channel region, a carrier mobility can be raised further.